Solar cell



FIG. 1 is a top perspective view of a solar cell showing my new design;

FIG. 2 is a top plan view thereof, the bottom plan view being the same as the top plan view;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a rear elevation view thereof; and,

FIG. 5 is a right elevation view thereof, the left side elevation view being the same as the right side elevation view. 

CLAIM The ornamental design for a solar cell, as shown and described. 